Driven by a desire to find new structural polysaccharides using enzymatic syntheses or genetic engineering of microorganisms or plant hosts, researchers have discovered polysaccharides that are biodegradable, and that can be made economically from renewable resource-based feedstocks. One such polysaccharide is poly alpha-1,3-glucan, a glucan polymer characterized by having alpha-1,3-glycosidic linkages. This polymer has been isolated by contacting an aqueous solution of sucrose with a glucosyltransferase enzyme isolated from Streptococcus salivarius (Simpson et al., Microbiology 141:1451-1460, 1995). Films prepared from poly alpha-1,3-glucan tolerate temperatures up to 150° C. and provide an advantage over polymers obtained from beta-1,4-linked polysaccharides (Ogawa et al., Fiber Differentiation Methods 47:353-362, 1980).
U.S. Pat. No. 7,000,000 disclosed the preparation of a polysaccharide fiber comprising hexose units, wherein at least 50% of the hexose units within the polymer were linked via alpha-1,3-glycosidic linkages using an S. salivarius gtfJ enzyme. This enzyme utilizes sucrose as a substrate in a polymerization reaction producing poly alpha-1,3-glucan and fructose as end-products (Simpson et al., 1995). The disclosed polymer formed a liquid crystalline solution when it was dissolved above a critical concentration in a solvent or in a mixture comprising a solvent. From this solution continuous, strong, cotton-like fibers, highly suitable for use in textiles, were spun and used.
Kiho et al. (Carb. Res. 189:273-270, 1989) and Zhang et al. (Intl. Publ. No. CN1283633) disclosed producing the ether-derivatized poly alpha-1,3-glucan, carboxymethylglucan. Yui et al. (Int. J. Biol. Macromol. 14:87-96, 1992) and Ogawa et al. (Carb. Poly. 3:287-297, 1983) disclosed esterifying poly alpha-1,3-glucan to produce poly alpha-1,3-glucan triacetate.
Development of new poly alpha-1,3-glucan derivatives (e.g., oxidized poly alpha-1,3-glucan) and methods of preparing such derivatives is desirable given their potential utility in various applications.